Internally gimbaled attitude indicator



June 2, 1970 GJL. SNIDER INTERNALLY GIMBALED ATTITUDE INDICATOR 5 Sheets-Sheet 1 Filed May 20, 1968 F /G. PRIOR ART FORWARD TRANSMISSION NETWORK FIG 3 INVENTQR.

NIDER GERALD L. 3 BY AT OR Y?" June 2, 1970 e. L. SNIDER INTERNALLY GIMBALED ATTITUDE INDICATOR v 3 Sheets-Sheet 2 Filed May 20, 1968 in v ATTORNEY June 2, 1970 G. L. SNIDER INTERNALLY GIMBALED ATTITUDE INDICATOR :5 Sheets-Sheet 5 Filed May 20, 1968 will!!! If FIG 5 ATTORNEY 3,516,055 INTERNALLY GIMBALED ATTITUDE INDICATOR Gerald L. Snider, Grand Rapids, Mich., assignor to Lear Siegler, Inc. Filed May 20, 1968, Ser. No. 730,233 Int. Cl. G01c 19/44; G08c 21/00 U.S. Cl. 340-27 18 Claims ABSTRACT OF THE DISCLOSURE An aircraft attitude indicator includinga pair of generally hemispheric shape display surfaces which are rotatably mounted on a pair of canted shafts secured to a support housing for providing a pitch indication. The

support housing itself is rotatably supported by a shaft which extends between the display surfaces for providing a roll indication. The display surfaces are operably connected; e.g., by gear teeth or friction drive means so that movement of one display surface will effect the movement of the other. The positions of the display surfaces in pitch and roll are controlled by conventional servo loops, with the pitch position servo loop being closed by the meshing of the display surfaces.

indicate the aircrafts attitude.

Generally, such indicators fall into two categories; i.e., case contained and remote reading. Case contained indicators are those in which the gyro sensing means is located internally of the visual display means. In contradistinction, remote reading indicators are those in which the gyro sensing means is positioned outwardly of and remote from the visual display means.

Unfortunately, both the case contained and remote reading attitude indicators of the prior art have many inherent deficiencies. The case contained indicators particularly suffer from problems of size, weight and accuracy while the remote reading attitude indicators are especially prone to vibration, shock and size problems. Thus, it was in response to the above-outlined deficiencies of prior art attitude indicators, that the present invention evolved.

Accordingly, it is an object of the instant invention to provide a smaller and lighter attitude indicator than heretofore available.

Another object of this invention is to provide an attitude indicator that is more reliable and easier to inspect and service than prior art indicators.

It is another object of this invention to provide a less expensive and more reliable attitude indicator than previously available.

A further object of this invention is to provide an attitude indicator having improved tolerance to shock and vibration.

Other objects and many of the attendant advantages of United States Patent 3,516,055 Patented June 2, 1970 ice the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings illustrating one embodiment of the instant invention, wherein:

FIG. 1 is a simplified perspective of a prior art remote reading attitude indicator;

FIG. 2 is a simplified perspective of the subject invention, partly in section;

FIG. 3 is a front elevation of the present invention;

FIG. 4 is a simplified cross section of the present invention taken along line IVIV of FIG. 3; and

FIG. 5 is a simplified cross section of the present invention taken along line VV of FIG. 3.

Before proceeding, it should be noted that the above drawings particularly illustrate the prior art with respect to one axis; e.g., the pitch axis of a dirigible craft and the present invention with respect to both the roll and pitch axes of such a craft. Accordingly, it should be appreciated that the concepts described hereinbelow apply with equal force to the other axes of such a craft.

#Referring again to the drawings, and more particularly to FIG. 1, a prior art remote reading attitude indicator is shown generally at 10 and is controlled by signals from a gyro platform 12. The platform 12 includes a pitch synchro transmitter 13 and is commonly positioned within a craft at a position remote from the indicator 10.

The indicator 10 includes a shaft 15 which functions to provide a roll indication on the indicator in a well-known manner. The shaft 15 is connected to a yoke 17 which serves as a gimbal frame for a visual display 19. The dis play 19 is fixed to a shaft 21 which extends diammetrically therethrough and is rotatably supported within the yoke 17.

One end of the shaft 21 is connected to a control transformer 23 and the other end of said shaft 21 is connected to a DC torque motor 25. The control transformer 23 is electrically connected to the pitch synchro transmitter 13 and through a forward transmission network to the DC torque motor 25.

Basically, when the craft undergoes a change in pitch, a signal is sent by the transmitter 13 to the control transformer 23 where the position of the shaft 21 (and of course the display 19) is compared with the position indicated by the signal from the transmitter 13.

Elf the shaft position and the signal position do not correspond, an error signal is sent through the servo-loop to the DC torque motor which will rotate the shaft 21 and its associated display 19 to the position indicated by the transmitter 13. Obviously, the angular position of the display 19, about an axis extending through the shaft 21, will be indicative of the pitch of the craft. For a more detailed explanation of this prior art remote reading type indicator system reference may be had to copending U.S. patent application, Ser. No. 643,685, filed June 5, 1967.

Returning to the present invention, and referring again to FIG. 2, a remote reading attitude indicator is shown generally at 30 including a case 32 having a viewing window 34. A mounting plate 36 is fixedly mounted within the rear portion of said case 32 and supports a hollow shaft 38 which is aflixed thereto at one end portion and extends axially within said case 32 toward said window 34.

As best seen in FIG. 4, the shaft 38 extends axially 3 through a support housing 40 which extends outwardly of said shaft 38 to face plates 42 and 44, respectively, said housing 40 being rotatably supported by said shaft 38. The plates 42 and 44 are affixed to and form a part of the housing 40 and are canted with respect to one another so as to converge toward the window 34.

A DC torque motor 46 and a follow-up synchro or control transformer 48 are disposed within said support housing 40, and extend outwardly of the shaft 38 in opposite directions. The torque motor 46 and the control transformer 48 include rotor shafts 50 and 52, respectively, which extend outwardly of the support housing 40 in opposite directions. The torque motor 46 and the control transformer 48 are fixed to the opposite face plates 44 and 42, respectively, and the shafts 50 and 52 extend outwardly of and normal to said face plates 44 and 42 so that their axes are canted.

As best seen in FIGS. 2 and 4, first and second display surfaces 54 and 56, of generally oblate hemispheric shape, are fixedly mounted at their poles to the canted rotor shafts 50 and 52, respectively, and are rotatable therewith.

The display surface 54 extends to a female lip 58, about the inner periphery of which a plurality of teeth 81 are disposed. The display surface 56 extends to a male lip 62 which includes a plurality of teeth 64 disposed about its outer periphery.

The display surfaces 54 and 56 are canted with respect to each other, and diverge in a direction, along the axis of the shaft 38, toward the mounting plate 36 so as to permit the shaft 38 to extend between them without contact.

Referring now to FIGS. 2 and 3, both of the display surfaces 54 and 56 are shown to include indicia 66 thereon. A portion of the male lip 62 of the display surface 56 is received by a portion of the female lip 58 of the display surface 54 so that their respective teeth 64 and 81 mesh and the indicia on said displays 54 and 56 align to provide a uniform display when viewed through the window 34. Obviously, any suitable friction drive means between the surfaces 54 and 56 may be substituted for the meshing teeth 64 and 81.

Suitable control signals may be provided tothe DC torque motor 46 and the control transformer 48 by e1ec trically connecting them to an external signal source; e.g., a pitch synchro transmitter (not shown) by passing electrical conductors from such source through the hollow shaft 38 to a slip ring assembly 68 afiixed thereto. Electrical connection between the slip ring assembly 68, and both the DC torque motor 46 and the control transformer 48 may be made in a well-known manner, as by brush blocks (not shown) aflixed to the housing 40 and in contact with the slip ring assembly 68.

As best seen in FIG. 5, the housing 40 includes a pair of oppositely-directed support plates 70 and 72 rotatable therewith and which extend outwardly of the shaft 38 and the display surfaces 54 and 56. It will be recalled that said display surfaces 54 and 56 are canted with respect to each other and diverge toward the mounting plate 36. This divergence is such as to admit the support plates 70 and 72 between the surfaces 54 and 56 without any contact.

A second control transformer 74 and a second DC torque motor 76 are fixed to the support plates 70 and 72, respectively. The control transformer 74 and the torque motor 76 include rotor shafts 78 and 80, respectively. The shaft 80 includes a plurality of teeth disposed about the periphery thereof to form a pinion which engages a gear 82 fixed to the shaft 38. A gear 84 is fixedly secured to the shaft 78 and engages a gear 86 which is fixedly secured to the shaft 38 and the gear 82.

Suitable control signals may be provided to the DC torque motor 76 and the control transformer 74 by electrically connecting them to an external signal source, e.g., a roll synchro transmitter (not shown), by passing 4 electrical conductors from such source through the hollow shaft 38 to the slip ring assembly 68. Electrical connection between the slip ring assembly 68, and both the DC torque motor 76 and the control transformer 74 may be made in a well-known manner as by brush blocks (not shown) afiixed to the housing and in contact with the slip ring assembly 68.

Referring again to FIG. 3, a bezel 88 is shown surrounding the window 34 and includes a plurality of radially disposed reference markings 90 thereon. Additionally, generally horizontal reference markings 92 appear on the face of the window 34. Further, a pointer assembly 94 is affixed to each of the support plates 70 and 72 and extends over one of the display surfaces 54 and 56 inwardly of the bezel 88. The pointer assemblies 94 rotate with the housing 40 and the display surfaces 54 and 56 about the hollow shaft 38.

In operation, control signals from; e.g., the pitch synchro transmitter, may be applied to the control transformer 48. Said transformer 48 is connected to the display surface 56 which, in turn, is geared to rotate with the display surface 54 about the canted axes of the shafts 52 and 50, respectively.

Thus, the angular position of the display surface 54 (about the axis of the shaft will be sensed by the control transformer 48 and compared with the signal from the pitch synchro transmitter.

If there is a discrepancy between the position of the display surface 54 (and, of course, the display surface 56) and that dictated by the pitch synchro transmitter signal, then an error signal will be provided by the control transformer 48 to the DC torque motor 46.

The DC torque motor 46 will rotate the display surface 54 to the position indicated by the pitch synchro transmitter. The display surface 56 will rotate with the display surface 54 and will also rotate the shaft 52 (to which it is affixed) so as to null the control transformer 48.

In an analogous manner, position signals may be sent; e.g., from a roll synchro transmitter v(not shown), to

the control transformer 74. Said transformer 74 will, via

the gears 84 and 86, sense the angular position of the housing 40 and the display surfaces 54 and 56 (which rotate therewith) with respect to the shaft 38. The angular position of the housing 40 and said surfaces 54 and 56 will be compared with that indicated by the signal from the roll synchro transmitter. If there is a discrepancy, an error signal will be transmitted by the control transformer 74 to the DC torque motor 76, which, via the pinion 80 and gear 82, will rotate the housing 40 and the display surfaces 54 and 56 to the position indicated by the roll synchro transmitter signal so as to null the control transformer 74. Obviously, the support plates and 72 (and the transformer 74 and motor 76 respectively attached thereto) will rotate with the housing 40 and the display surfaces 54 and 56.

Of course, as best seen in FIG. 3, rotation of the display surfaces 54 and 56 about the axes of the shafts 50 and 52, respectively, will be indicated by the position of the indicia 66 with respect to the reference markings 92. Analogously, rotation of the display surfaces 54 and 56 about the shaft 38 will be indicated by the position of the pointer assemblies 94 with respect to the reference markings 90.

It should be emphasized at this point that the rotation of the display surfaces '54 and 56 about the axes of the shafts 50 and 52, respectively is independent from the rotation of said display surfaces 54 and 56 about the shaft 38 and may occur simultaneously therewith. Also, rotation of said display surfaces 54 and 56 about the axes of the shafts 50 and 52, respectively, may be representative of a change in the attitude of a dirigible craft with respect to either the roll, pitch or azimuth axis of the craft. Likewise, rotation of the display surfaces 54 and 56 about the shaft 38 may be representative of a change in the attitude of a dirigible craft with respect to any of its axes.

' Having considered the structure and operation of one embodiment of the invention, it is appropriate to note that the conventional gimbal rings or yokes (see 17 in FIG. 1) of the prior art (used, for example, to provide pitch gimbaling) are eliminated by the subject invention. Accordingly, the invention may be characterized as being internally gimbaled due to the absence of any gimbaling ring or yoke surrounding the gimbaled structure or display means.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings and it will be readily apparent to those skilled in the art that various changes in form and arrangement of components may be made to suit requirements without departing from the spirit and scope of this invention. Accordingly, it is to be understood that within the scope of'ithe appended claims the present invention may be practiced in a manner otherwise than is specifically described, herein.

What is claimed is:

1. An indicator for displaying the position of a dirigible craft including:

support means;

first display means connected to said support means and rotatable relative thereto about an axis fixed therein';"'and second display means connected to said support means and rotatable relative thereto about an axis fixed therein canted with respect to that of said first display means, said second display means cooperable and in contact with said first display means so as to provide a continuous and unified visual display.

2. The invention as set forth in claim 1, further including means for rotatably mounting said support means,

whereby each of said display means may resolve about an axis oblique :to its respective axis of rotation.

3. The invention of claim 1, wherein said first and second display means are operably connected so that rotation of one of them will effect like rotation of the other of them.

4. The invention as set forth in claim 3, further including means for rotatably mounting said support means, whereby said display means may revolve about a common axis oblique to their respective axes of rotation.

5. The invention as recited in claim 4, additionally including:

means connected to one of said display means for generating a signal indicative of the angular displacement of the other of said display means for a predetermined position; and

means connected to said other of said display means and to said signal generating means for rotating said other of said display means to said predetermined position thereby nulling said signal generating means.

6. The invention as set forth in claim 5, wherein said first and second display means each comprise a graduated generally hemispheric surface.

7. The invention as recited in claim 6, wherein one of said hemispheric surfaces extends to a male lip having a plurality 'ofi teeth disposed about the periphery thereof, and the other} of said hemispheric surfaces extends to a female lip haying a plurality of teeth disposed about the periphery thereof, said hemispheric surfaces cooperable to enable their respective teeth to mesh.

8. The invntion of claim 7, wherein said signal generating means comprises a control transformer and said display means rotating means comprises a DC torque motor.

9. The invention as recited in claim 3, additionally including:

means connected to one of said display means and to said support means for generating a signal indicative of the angular displacement of the other of said display means about its said rotational axis from a predetermined position relative to said support means; and

means connected to said other of said display means and to said support means and operably connected to said signal generating means for rotating said other of said display means to said predetermined position thereby nulling said signal generating means.

10. The invention as set forth in claim 9, wherein said first and second display means each comprise a graduated generally hemsipheric surface.

11. The invention as recited in claim 10, wherein one of said hemispheric surfaces extends to a male lip having a plurality of teeth disposed about the periphery thereof and the other of said hemispheric surfaces extends to a female lip having a plurality of teeth disposed about the periphery thereof, said hemispheric surfaces cooperable to enable their respective teeth to mesh.

12. The invention of claim 11, wherein said signal generating means comprises a control transformer and said display means rotating means comprises a DC torque motor.

13. In an indicator for displaying the attitude of a dirigible craft in response to signals from an external source, the combination including:

plural display means in contact with and rotatable relative to one another and each having indica on the surface thereof and together providing a unified visual display and forming an enclosure at the reverse side thereof;

gimbaling means internally of said enclosure for supporting each said display means for rotation relative thereto about an axis fixed in said gimbaling means, and

means for rotatably mounting said gimbaling means.

14. The invention as set forth in claim 13, wherein said plural display means comprises first and second p0rtions each having an axis of rotation canted with respect to that of the other and wherein said gimbaling means is supported by said mounting means so that said first and second portions may each turn relative to said mounting means about an axis in said mounting means oblique to its respective axis of rotation.

15. The invention as set forth in claim 14, additionally including:

means connected to one of said display means portions for generating a signal indicative of the angular displacement of the other of said display means portions from a predetermined position; and means connected to said other of said display means portions and operably connected to said signal generating means for rotating said other of said display means portions to said predetermined position,

said one and said other of said display means portions being operably connected so that rotation of one of them will effect like rotation of the other of them.

16. A remote reading attitude indicator, including:

plural display means having indicia on the surface thereof in contact with and rotatable relative to one another and each capable of rotation about an axis so as together to provide a continuous and unified visual display;

means connected to one of said display means for generating a signal indicative of the angular displacement of the other of said display means from a predetermined position, and

means connected to said other of said display means and operably connected to said signal generating means for rotating said other of said display means to said predetermined position,

said one and said other of said display means being operably connected so that rotation of one of them will effect like rotation of the other of them.

17. The invention of claim 16, wherein said plural display means comprises a pair of graduated generally hemispheric surfaces.

18. The invention of claim 17, wherein each of said pair of hemispheric surfaces rotates about an axis canted with respect to that of the other of said pair of hemispheric surfaces.

References Cited UNITED STATES PATENTS 8 Vibert; 1 ..-..1 Ducomrnun 5 8-'126 .X

Schweighofer et a1. 1 Summers.

Reichel et a1. Kliever.

FOREIGN PATENTS France.

France.

Germany.

Great Britain. Great Britain. Great Britain.

HULL, Primary E aminer,

U.S. c1. X.R. I 

